"His heart was filled and pierced with enchantment and with the desire of dwarves" seems to indicate that two forces were at work:

The first I'll grant might be what is called "the dragon sickness." Something, some sort of spell, that can afflict anyone who gazes upon a dragon's hoard.

The second, "the desire of dwarves" seems to be a pre-existing trait belonging to dwarves; not necessarily dependant on the existence of a dragon hoard. Given what else we know from the tale, the condition is likely pride, lust (for gold, though one wonders given that dwarf women are bearded...), and greed rolled into one.

So it would be fair to say that even if it was not Thorin's prime motivation for reclaiming the treasure, as a pre-existing condition, that pride, lust and greed likely played a part. Even before observing the treasure.

However, from sador's observations as well (unless I missed the context) Thorin had already spent time with at least part of the treasure. So either it carried a curse of its own (pre-Smaug), or the desire for it at any cost was endemic to dwarves (ie as any hoard would be)... or both. The fact that it was hoarded before Smaug appeared -- though was added to from neighbouring sources as he did -- is an important point here.

The predisposition towards being greedy may indeed be, as sador also points out, a throw back to Tolkien's earlier (pre-Hobbit) ideas about dwarves, but that he ultimately intended to discard. (A notion I was only just made aware of here, thank you sador.)

Still, I am reminded of the point dormouse has been making about the key descriptor "hoarded." The word does not simply imply the act of amassing a great treasure, but also implies that it is not shared or otherwise used to anyone's (including the hoarder's) benefit. Therefore greed, more so than pride even, is what Thorin laments in his final moments.

Be that as it may, despite his many faults, ultimately I do not see Thorin as someone who is beyond redemption. Nor do I believe that he is much different (except in the details) from any other of Tolkien's complex characters, all who exhibit faults of their own. I guess the extent to which their flaws lead to their downfall (or not!) is something to be kept in mind while reading Tolkien.

And yes, to your other recent post, this has been a robust discussion! I'm quite enjoying it and learning a lot in the process... thank you to isaac and all who have participated.